Conventional knitting units of circular knitting machines are traditionally associated with more than 100 yarn supply bobbins. Waste fibers are generated by engagement of the yarn with the machine's yarn feeding, guiding and/or knitting components. The waste fiber problem is aggravated by the fact that knitting machines are being operated at increasingly faster speeds. The dust, lint and waste fibers generated-accumulate on the knitting components of the knitting unit, such as the needle and the sinker grooves. This dust, lint and waste fibers occasionally gets knitted into the fabric causing defects in the fabric and in some cases, causing damage to the needles and other components of the knitting unit. This accumulation of dust, lint and waste fibers necessitates frequent over hauls of the knitting units on the machine which is both costly and time consuming.
Various types of air blowing cleaning devices have been provided for blowing away dust, lint and waste fibers before they can accumulate to a point where the dust, lint and waste fibers can cause damage to the knitting machine and/or the fabric. These devices usually include one or more injection tubes or nozzles which have tip openings located adjacent the positions where dust, lint and waste fibers are generated. Several of these air injection nozzles are usually employed on a knitting machine, especially a circular knitting machine. These air injection nozzles blow dust, lint and waste fibers away that gather in certain parts while rotating in the same direction as the rotating cylinder or while rotating in a direction opposite to the rotating cylinder. An example of such an arrangement may be found in Japanese Patent Publication No. SHO 52-33705.
Although it is possible to remove dust, lint and waste fibers over a wide range by injecting air from the tip opening of the injection nozzle and by oscillating the nozzle regularly, as disclosed in U.S. Pat. No. 4,691,536 assigned to Applicant, air does not reach the dust, lint and waste fibers that are generated during the process of forming the yarn into stitches using the knitting needles and sinkers. Dust, lint and waste fibers that are not reached by air go into and accumulate in the sinker grooves, making it more difficult to be blown away. Without lubrication, movement of the working parts of the knitting unit causes increased friction and wear, as well as generating increased dust and damage to the fabric being worked.